Rename "snippets" to "conf" internally, and document them as snippets

Discussed in #2896.

Makefile.in

@@ -55,7 +55,7 @@ docdir = @docdir@
 localedir = @localedir@
 extra_completionsdir = @extra_completionsdir@
 extra_functionsdir = @extra_functionsdir@
-extra_snippetsdir = @extra_snippetsdir@
+extra_confdir = @extra_confdir@
 
 #
 # pcre2
@@ -472,7 +472,7 @@ doc.h: $(HDR_FILES)
 		-e "s,@docdir\@,$(docdir),g" \
 		-e "s,@extra_completionsdir\@,$(extra_completionsdir),g" \
 		-e "s,@extra_functionsdir\@,$(extra_functionsdir),g" \
-		-e "s,@extra_snippetsdir\@,$(extra_snippetsdir),g" \
+		-e "s,@extra_confdir\@,$(extra_confdir),g" \
 		-e "s|@configure_input\@|$@, generated from $@.in by the Makefile. DO NOT MANUALLY EDIT THIS FILE!|g" \
 		-e "s,@prefix\@,$(prefix),g" \
 		-e "s,@fish_build_version\@,$(FISH_BUILD_VERSION),g" \
@@ -665,7 +665,7 @@ install-force: all install-translations
 	$(INSTALL) -m 755 -d $(DESTDIR)$(datadir)/fish/completions
 	$(INSTALL) -m 755 -d $(DESTDIR)$(extra_completionsdir)
 	$(INSTALL) -m 755 -d $(DESTDIR)$(extra_functionsdir)
-	$(INSTALL) -m 755 -d $(DESTDIR)$(extra_snippetsdir)
+	$(INSTALL) -m 755 -d $(DESTDIR)$(extra_confdir)
 	$(INSTALL) -m 755 -d $(DESTDIR)$(datadir)/fish/functions
 	$(INSTALL) -m 755 -d $(DESTDIR)$(datadir)/fish/man/man1
 	$(INSTALL) -m 755 -d $(DESTDIR)$(datadir)/fish/tools

configure.ac

@@ -877,12 +877,12 @@ AC_ARG_WITH([extra_functionsdir],
             [extra_functionsdir=$withval],
             [extra_functionsdir='${datadir}/fish/vendor_functions.d'])
 
-AC_SUBST(extra_snippetsdir)
-AC_ARG_WITH([extra-snippetsdir],
-            AS_HELP_STRING([--with-extra-snippetsdir=DIR],
-                           [path for extra snippets]),
-            [extra_snippetsdir=$withval],
-            [extra_snippetsdir='${datadir}/fish/vendor_conf.d'])
+AC_SUBST(extra_confdir)
+AC_ARG_WITH([extra-confdir],
+            AS_HELP_STRING([--with-extra-confdir=DIR],
+                           [path for extra conf]),
+            [extra_confdir=$withval],
+            [extra_confdir='${datadir}/fish/vendor_conf.d'])
 
 # Tell the world what we know.
 AC_CONFIG_FILES([Makefile])

doc_src/index.hdr.in

@@ -1111,7 +1111,7 @@ On startup, Fish evaluates a number of configuration files, which can be used to
 Configuration files are evaluated in the following order:
 - Configuration shipped with fish, which should not be edited, usually `/usr/share/fish/config.fish`.
 - System-wide configuration files, where administrators can include initialization that should be run for all users on the system - similar to `/etc/profile` for POSIX-style shells - usually `/etc/fish/config.fish`;
-- "Unit" configuration files ending in `.fish`, in the directories:
+- Configuration snippets in files ending in `.fish`, in the directories:
   - `~/.config/fish/conf.d/`
   - `/etc/fish/conf.d`
   - `/usr/share/fish/vendor_conf.d`

fish.pc.in

@@ -2,7 +2,7 @@ prefix=@prefix@
 datadir=@datadir@
 completionsdir=@extra_completionsdir@
 functionsdir=@extra_functionsdir@
-confdir=@extra_snippetsdir@
+confdir=@extra_confdir@
 
 Name: fish
 Description: fish, the friendly interactive shell

share/__fish_build_paths.fish.in

@@ -1,8 +1,8 @@
 # @configure_input@
 # This function is generated by the autotools build to "compile in"
-# the local "vendor" completions, functions and configuration snippets.
+# the local "vendor" completions, functions and configuration conf.
 # It is sourced by share/config.fish, if it exists.
 
 set __extra_completionsdir @extra_completionsdir@
 set __extra_functionsdir @extra_functionsdir@
-set __extra_snippetsdir @extra_snippetsdir@
+set __extra_confdir @extra_confdir@

share/config.fish

@@ -49,7 +49,7 @@ end
 # third-party packages to ship completions &c.
 set -l __extra_completionsdir
 set -l __extra_functionsdir
-set -l __extra_snippetsdir
+set -l __extra_confdir
 if test -f $__fish_datadir/__fish_build_paths.fish
     source $__fish_datadir/__fish_build_paths.fish
 end
@@ -166,7 +166,7 @@ end
 # As last part of initialization, source the conf directories
 # Implement precedence (User > Admin > Extra (e.g. vendors) > Fish) by basically doing "basename"
 set -l sourcelist
-for file in $configdir/fish/conf.d/*.fish $__fish_sysconfdir/conf.d/*.fish $__extra_snippetsdir/*.fish
+for file in $configdir/fish/conf.d/*.fish $__fish_sysconfdir/conf.d/*.fish $__extra_confdir/*.fish
 	set -l basename (string replace -r '^.*/' '' -- $file)
 	contains -- $basename $sourcelist; and continue
 	set sourcelist $sourcelist $basename